1. Field of the Invention
The application relates generally to pumps having a pony rod and a plunger in operative communication with a fluid end and, more particularly, to a tool for coupling the plunger to the pony rod.
2. Description of Related Art
It is difficult to economically produce hydrocarbons from low permeability reservoir rocks. Oil and gas production rates are often boosted by hydraulic fracturing, a technique that increases rock permeability by opening channels through which hydrocarbons can flow to recovery wells. During hydraulic fracturing, a fluid is pumped into the earth under high pressure (sometimes as high as 50,000 PSI) where it enters a reservoir rock and cracks or fractures it. Large quantities of proppants are carried in suspension by the fluid into the fractures. When the pressure is released, the fractures partially close on the proppants, leaving channels for oil and gas to flow.
Specialized pumps are used to deliver fracture fluids at sufficiently high rates and pressures to complete a hydraulic fracturing procedure or “frac job.” These pumps are usually provided with fluid ends having both reciprocating plungers that place fluids under pressure and valves that control fluid flow to and from the plungers. Fluid ends have many parts that are releasably fastened to one another so that they can be easily repaired or replaced. For example, plungers are typically threadedly coupled to a pony rod, the pony rod inducing movement of the plunger. It is the connections between the parts and the supporting features for the valves that tend to weaken a fluid end, limiting its pressure rating, and making it susceptible to corrosion, leaks, and cracks under high, cyclical stresses. Thus, fluid ends sometimes fail under load prematurely.
As the plungers reciprocate within the pumping chamber, the plungers cycle between high and low pressures and are subjected to high stress variations. The plungers also rub against sealing elements in the ends of the pumping chambers and, consequently, are worn and abraded by proppants and other materials carried in the pumped fluids. Typically, the plungers are located deep within a fluid end of a pump that is held together by a large number of heavy, threaded fasteners. To access the worn plungers, the fluid end and other pump components must often be disassembled.
Manufacturers have made few provisions in pumps for fixing pump plungers as they wear out. Threaded connections between the pony rod and the plunger are susceptible to loosening during pumping operations, thereby requiring more maintenance. Additionally, the threads may become contaminated and scratched with debris requiring polishing. Although manufacturers provide strong and robust pumps, disassembly of pumps in the field is especially time-consuming and difficult to perform.
Although great strides have been made in fluid ends, considerable shortcomings remain.
While the system and method of the present application is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the application to the particular embodiment disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the process of the present application as defined by the appended claims.